CVE-2025-47280 in Forms
Summary
by MITRE • 05/13/2025
Umbraco Forms is a form builder that integrates with the Umbraco content management system. Starting in the 7.x branch and prior to versions 13.4.2 and 15.1.2, the 'Send email' workflow does not HTML encode the user-provided field values in the sent email message, making any form with this workflow configured vulnerable, as it allows sending the message from a trusted system and address, potentially bypassing spam and email client security systems. This issue affects all (supported) versions Umbraco Forms and is patched in 13.4.2 and 15.1.2. Unpatched or unsupported versions can workaround this issue by using the `Send email with template (Razor)` workflow instead or writing a custom workflow type. To avoid accidentally using the vulnerable workflow again, the `SendEmail` workflow type can be removed using a composer available in the GitHub Security Advisory for this vulnerability.
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Analysis
by VulDB Data Team • 05/13/2025
CVE-2025-47280 represents a critical server-side template injection vulnerability within Umbraco Forms that affects versions 7.x through 13.4.1 and 15.1.1. This vulnerability stems from insufficient input sanitization in the email workflow functionality where user-provided field values are not properly HTML encoded before being included in email messages. The flaw manifests when the 'Send email' workflow processes form submissions, allowing attackers to inject malicious content that gets rendered in the email body without proper sanitization. This issue aligns with CWE-79, which describes Cross-Site Scripting (XSS) vulnerabilities resulting from improper encoding of user input. The vulnerability is particularly dangerous because it leverages the trusted relationship between the Umbraco system and email clients, enabling attackers to craft emails that bypass standard spam filters and security mechanisms.
The technical exploitation of this vulnerability occurs when an attacker submits malicious input through form fields that are then processed by the vulnerable email workflow. The lack of HTML encoding means that any HTML or script content entered by users gets directly embedded into the email message body, potentially allowing for the execution of malicious scripts in email clients that support such functionality. This creates a vector for phishing attacks, credential harvesting, and other malicious activities that exploit the trust relationship between the email sender and recipient. The vulnerability affects all supported versions of Umbraco Forms, making it a widespread concern for organizations using this content management system integration. The issue demonstrates poor input validation and output encoding practices that are fundamental to preventing XSS attacks as outlined in the OWASP Top Ten and MITRE ATT&CK framework's T1566.601 technique for Phishing via Social Engineering.
The operational impact of CVE-2025-47280 extends beyond simple data exposure, as it creates opportunities for attackers to establish persistent threat vectors through email-based attacks. Organizations may experience compromised user trust, potential data breaches, and increased spam filtering complications due to the malicious email content being sent from legitimate system addresses. Email security systems that rely on sender reputation and content analysis may be bypassed, leading to successful phishing campaigns that appear to originate from trusted sources within the organization. This vulnerability particularly affects organizations that rely heavily on form submissions for user interactions, customer feedback, or business processes where email notifications are critical. The impact is amplified when considering that this vulnerability affects multiple version branches of Umbraco Forms, requiring organizations to implement comprehensive patch management strategies across their systems. The mitigation approach includes upgrading to versions 13.4.2 or 15.1.2, which contain proper HTML encoding implementations, or implementing alternative workflows such as the 'Send email with template (Razor)' option that provides better security controls.
Organizations should implement immediate remediation measures by applying the available patches for Umbraco Forms versions 13.4.2 and 15.1.2, as these releases contain the necessary HTML encoding fixes for the vulnerable workflow. The workaround of using the 'Send email with template (Razor)' workflow provides a temporary solution while organizations prepare for the full patch deployment. Additionally, the recommended approach of removing the vulnerable `SendEmail` workflow type through a custom composer offers a more permanent solution for environments where immediate patching is not feasible. Security teams should also conduct thorough vulnerability assessments to identify all instances where the vulnerable workflow is currently configured, particularly in environments with high user interaction or sensitive data collection processes. The remediation process should include monitoring email traffic for signs of exploitation attempts and implementing additional email security controls to detect and prevent potential abuse of the vulnerability. Organizations should also review their broader security posture to ensure that similar encoding issues do not exist in other components of their Umbraco installations or related systems.